1. Field of the Art
The present invention relates in general to a method of drying a formed ceramic mass and a jig used to practice the method, and more particularly to such method and jig which are effective to protect the formed ceramic mass against deformation or distortion during drying thereof.
2. Related Art Statement
Silicon ceramics such as silicon nitride, silicon carbide, and SIALON, alumina ceramics, zirconia ceramics and other ceramics are more stable at elevated temperatures and more resistant to oxidation-corrosion and creep-stresses than metals. In the light of these advantages, research and development are actively conducted in the industry, to utilize such ceramics for engine parts and other components that are exposed to high operating temperatures.
In the art of producing ceramic parts as indicated above, a ceramic powder is mixed with suitable binder, water, solvent, forming-aids and other necessary agents. The obtained mixture is formed into a desired shape by extrusion, casting or other forming methods. The formed ceramic mass is then dried to remove the water, solvent and other substances added to the ceramic powder. Subsequently, the dried ceramic mass is fired or sintered. Thus, the intended ceramic part (ceramic product) is prepared.
According to a known process, the step of drying a formed ceramic mass in the process of fabricating a ceramic product is generally accomplished by placing the ceramic mass on a flat table located within a suitable drying vessel or furnace, and heating the ceramic mass.
In such a drying method in the known process, however, the formed ceramic mass tends to suffer distortion or strain at its walls which define holes that are open in the end faces of the ceramic mass. The distortion of these holes has an adverse influence on the quality or function of the dried ceramic mass as an end product. The dried ceramic mass, if heavily distorted, may lose its commercial value as a product. In particular, a formed ceramic body for a structure having many apertures or holes or a honeycomb structure, such as a ceramic rotor for a pressure-wave supercharger, is subject to circumferential deformation or distortion at its end face or faces in which the apertures are open. Consequently, the apertures of the honeycomb structure may not be correctly formed as designed, whereby the obtained honeycomb structure may not satisfy the practical requirements.